Conelrad warning device with motor driven switch for operating capacitor charging means



3,246,246 WITCH FQR April Z, 1966 B. F. CRAIG VICE WITH MOTOR DRIVEN SEANS CONELRAD WARNING DE OPERATING CAPACITOR CHARGING M Filed Nov. 8,1961 United States Patent O CONELRAD WARNING DEVICE WITH MOTOR DRIVENSWITCH FOR OPERATING CAPACITR CHARGING MEANS Bryant F. Craig, Arlington,Tex., assignor to Amaiga Corporation, Dallas, Tex., a corporation ofTexas Filed Nov. 8, 1961, Ser. No. 150,910 7 Ciaims. (Cl. S25-466) Thisinvention relates to a radio warning device and more particularly to aradio receiver warning device for developing and delivering an audiblewarning of a conelrad alert.

More specifically, the present invention relates to an electronicallyactuated signal decoding7 apparatus, the operation of which is dependentupon the reception of radio frequency signals transmitted pursuant toand in accordance with the standard conelrad warning system.

The instant apparatus may be used in applications where an alertingsignal of the predetermined conelrad code actuates a decoding portion ofthe apparatus which in turn causes a standard superheterodynetransistorized radio receiver to be activated so as to render a signalreproducing device operative and thereby result in an audibleannouncement of an impending and imminent national emergency.

Copending application Serial No. 123,469, filed July l2, 1961, in thenames of Craig and McCartney, discloses a warning device for use in thehomerwhich warning device takes the form of a small transistor radioreceiver. The present invention relates to a warning device of the typedisclosed in said copending application but provides a mechanicaldecoder portion for uniquely responding to the conelrad warning systemand for rendering such device capable of emitting an audible warning ofan impending and imminent national emergency.

In the past, numerous devices and systems capable of providing radiowarnings of an impending disaster, such as, air raid warnings, hurricaneand tornado warnings, police alerts, or fire warnings, have beendeveloped and known in corresponding technical and scientific areas.None of these systems, however, is suited for use in conjunction withthe standard conelrad system. In general, most of the prior knowndevices and systems require highly complicated equipment andunreasonably expensive circuit components for performing the purpose forwhich the devices were created.

Further, most of the heretofore known radio warning systems and devicesrequired specific and cumbersome attachment thereof to existingsuperheterodyne radio receivers commonly found in civilian, industrialand governmental sites. Such arrangements were often objectable in thatthe normal operation or use of the radio receiver was impaired or thecost for connecting the device or system thereto was considerable.

Stillrfurther, most of the prior known radio Warning systems or deviceswere unreliable, ineffective and inefficient in performing the functionintended should the commonly available 110 volt, 60 cycle, A.C. powersupply be disconnected. That `is to say, the receipt of a warning of animpending disaster or the like was not perfected in the event thatconventional A.C. power commonly available in this country isdisconnected for one reason or the other.

Further, most of the heretofore known radio warning systems reliedprincipally upon the fact that, in the event of a national emergency,modulation of the broadcast carrier frequency of standard transmittingstations would cease, thereby causing signalling means, such as lights,buzzers, bells, etc., to be activated. Such systems, however, are notpractical or effective, since there are often circumstances whenstandard transmitting stations only transmit a Vcarrier wave for shortperiods of time. It is apparent, therefore, that under such conditions,systems operating on the above-mentioned principle would emit falsealarms.

Still further, since it is obviously desirable to quickly alert thepopulace and instruct them on the proper course of action to be taken inthe event of a national emergency, many of the heretofore known systemshave suggested the use of centrally located loudspeakers.Y However, anobvious disadvantage, regarding centrally located loudspeakers, is thata sizeable port-ion of the populace may not hear the emergency -becauseof their physical 1ocation in respect to the loudspeakers.

The present invention avoids the above-mentioned difficulties byproviding a simplified and inexpensive device which is capable of eithercivilian, industrial or governmental use so that an audible indicationor warning may result in the event of a national emergency and whichdevice is particularly suited for use in conjunction with the standardconelrad warning system.

While the present invention may be used in a variety of industrial,governmental and civilian applications, the principle of operation makesit particularly useful for the unattended reception and decoding ofconelrad code signals. Accordingly, the present invention may be usedfor civil defense purposes, by the general public, by foperators ofradio ybroadcasting equipment and by commercial, industrial or amateurservices which are presently required by law to have available decodingequipment in order that radio broadcasting, except for civil defensepurposes, may be discontinued during a national emergency.

The heretofore known radio warning systems have required the continuousoperation of the entire warning device, whereas the device andprinciples of the present invention permit conventional superheterodynetransistorized radio receivers to be uniquely modified so as to receiveand decode conelrad alerts and yet not require the continuous fulloperation of the apparatus, thereby resulting in a noticeable economy ofoperation.

It is therefore a primary object of the present invention to provide anovel radio warning device capable of industrial, governmental andcivilian use.

Another object of the present invention is to provide a unique warningsystem for developing and delivering audible warnings of a nationalemergency.

A further object of the present invention is to provide a simplifiedreceiving unit for industrial, governmental or civilian use fordeveloping audible warnings of a Vnational emergency.

A still further object of the present invention is to provide a radiowarning device particularly suited for use in conjunction with theexisting conelrad Warning system.

A still further object of the present invention is to provide a novelradio warning device which is capable of giving an audible warning of anational emergency notwithstanding the destrutcion or discontinuance ofconventional A.C. power commonly used by radio receivers in thiscountry.

A yet still further object of the present invention is ,to provide amodified conventional superheterodyne transistorized receiver which iscapable of receiving conelrad `signal code and yet does not require thecontinuous full operation of the receiver apparatus thereby resulting ineconomy of operation.

A yet still further object of the present invention is to provide anovel radio warning device whereby a conelrad emergency signal codeactuates a decoding portion of the device which in turn causes theconventional radio receiver portion o-f the device to be actuatedthereby giving an audible warning of an impending national emergency.

It is vyet -a still further object of the present invention to provide amodified radio receiver warning device wherein a continuously operating,unattended, decoding circuit thereof is responsive to the conelradsignal code and which circuit automatically actuates an `alerting cir-Vcuit thereby resulting'in an audible warning of an impending nationaldisaster.

It is a still further object of the present invention Vto provide amodified radio receiver warning device wherein a continuously operating,unattended, decoding circuit thereof is responsive to the conelradsignal code and which circuit automatically actuates an alerting circuitthereby resulting in an audible Warning of an impending nationaldisaster.

It is a still further object of the present invention to provide -anovel emergency warning device particularly suited 'for use inconjunction With the existing conelrad warning system which device issimple in construction, economical to manufacture and highly reliable inperforming the function intended.

These and further `objects and advantages of the in-V vention will bemore apparent upon reference to the following specification, claims andappended Y drawings, wherein:

FIGURE l is a perspective view of the warning device of the presentinvention; and

v FIGURE 2 is a detailed circuit diagram of the novel portions of thereceiver warning device of the present invention for use in conjunctionwith the conelrad system.

While the present inventionrwill be described in conjunction with, andis particularly suited for, usek with the existing conelrad radiowarning system, it will be apparent that 'it has utility for use inconjunction with other warning systems, such as fire alarms, policealerts, flood alarms or other weather alerts.

In the event of a national emergency, such as an enemy bomber or missileattack, fire, hurricane or tornado warnings, police alerts, etc., it isdesirable to quickly l i Ul alert the public and instruct themen theproper course Y of action to be taken. In the specific case of an enemybomber or missile attack, it is well known that the general Public willhave very little warning and will have only a short time. to take cover,evacuate, or to make other arrangements essential to their protectionand survival during such attack. The time after general warning andbefore attack has been estimated by experts to be merely a matter ofminutes and even Ithe most optimistic estimates consider minutes asabout the greatest possible warning time present systems are able toprovide to theV general public.

While conventional air raid warning sirens to some extent provide auseable general warning system, they have many undesirable features,among which may beV listed the high expense of installation and upkeepalong with the periodic disturbance and annoyance when the sirens are-te-sted or inadvertently turned on.

In order to achieve the acme of performance and economy desired, thenovel and unique Warning device o-f the present invention wasincorporated in a small portable container in the form `and sizeof aconventional superheterodyne transistorized radio receiver, and made tobe removably vplugged into ythe conventional A.C. outlet of a home orother sites. tion uniquely provides a decoder for detecting the conelradsignal code.

By way of example, the current conelrad code consists of a standardbroadcast station carrier being first OFF five seconds, then ON fiveseconds, then OFF five seconds, then modulated with a thousand cyclesignal for fifteen seconds, and finally audio modulated withinstructions announcing the proper course of action to be taken in Viewof the specific impending disaster. When the The device of the presentinven-V yaudible war-ning whichV can be heard throughout an entirehousehold or other situs.

Further, the device of the prese-nt invention is operavtive throughoutan entire twenty-four hour day on an automatic basis, it does not dependupon the owner thereof having the conventionalreceiver portion of thedevice turned ON, and Vw-ill operate Yto warn the owner of an emergencyeven during the night when most are asleep.

Referring to FIGURE 1, the warning device of the present inventioncomprises a modified radio receiver generally indicated at 10 which isapproximately the size of a conventional transistorized radio receiverand includes a speaker 12, three button switch 14, and a cord 16 leadingto a plug 18 for insertion into the conventional 110 volt, 60 cyclepower outlet available in most 4homes or other situs.

The warning device of the present invention further includes: (l) theconventional RF antenna for receiving radio broadcast transmissions overthe commercial AM or FM radio broadcast bands; (2) the conventionalradio receiver RF and first IF stages; and (3) the conventional firstand second detector stages, all of which are omitted from FIGURE 2 forthe sake of clarity and simplicity of description.

The novel portion of the receiver of the present inventionis illustratedin detail in FIGURE 2 wherein the lead 21 receives the output from thesecond detector (not shown) of -a conventional receiver front end. Fromlead 21, the incoming signal passes through first and second -audioamplifier stages and is developed across the primary of a conventionaloutput transformer T2. f

Referring to FIGURE 2, wherein the warning ldevice of the presentinvention is shown in schematic representation, the lead 21, which isconnected to the second detector stage of the radioreceiver (not shown),isvconfnected to the upper end of resistor 22 whose lother end isconnected to B- source of potential 3-1. The incoming signal isdeveloped yacross variable resistor 22 and is fed to the base 32 oftransistor amplifier T R-4 through coupling capacitor 24 which has oneend connected to slider 26 of resistor 22 and the other end connected tobase 32. The base 32 of transistor 'IR-4 is connected to B-Asupply line31 by the resistor 28 and is connected to B-lsupply line 41 bytheresistor 30. The emitter 36 of transistor TR-4 is connectedv to B+supply line 31 through the parallel RC circuit comprising resistor 40and capacitorv 38. The amplified outputsignal from transistor rIll-4 isdeveloped across resistor 42 which has one end connected @to thecollector 34 and the other end connected to B- 4supply line 31.

The amplified output signal from transistor TR-4 is capacitively coupled`to base 50 of transistor amplifier TR-3 through coupling capacitor 46which has one end connected to Acollector 34 of transistor "FR-4 and theother end connected to base 50 of transistor TR-3. The base `50 of 'IR-3is connected to B- supply line 31 through resistor 44 and connected toB-isupply line 41 through resistor 48. YThe emitter of transistor TR-3is connected to B-lsupply line 41 through the parallel RC circuitcomprising resistor 58 and capacitor 56. f The amplified output signalof transistor 'IR-3 is developed across the primary 60 of outputtransformer TR-Z which has one end connected to collector 52 oftransistor TR-3 and the other end connectedY to B- supply line 31. Theoperation of transistor amplifiers 'TR-4 and TR-3 is conventional andwell known to those skilled in the prior art; therefore, a detailedexplanation thereof is not considered necessary.

Referring now to the lower lefthand portion of FIG- URE 2, there isshown the rectifying and filter circuit portion for providing theoperating potentials for the device of the present invention, theprimary of power transformer T-1 is coupled across a conventional 110volt, 60 cycle, A.C. source of supply, commonly available in homes andother sites and commonly used as the basic source of supply forsuperheterodyne radio receivers.

The 110 volt, A.C. potential is inductively`coupled across primary 160to secondary 162 of power transformer T-l. The upper end of secondary162 is connected to the cathode 155 of a diode rectiiier 156 and theanode 157 of that diode is connected to the junction of a tiltercapacitor 164 and limiting resistor 166. The other end of resistor 166is connected to filter capacitor 168 and the anode 159 of a second dioderectifier 158. The other ends of capacitors 164 and 168 are connected tothe lower end of secondary 162 of power transformer T-l. The cathode 261of diode rectier 158 is connected to the negative terminal of a storagebattery 170 and the positive terminal of storage battery 170 isconnected to the lower end of secondary 162 of power transformer T-1.The power transformer T-l is so wound that the voltage availablethereacross is approximately stepped down to six or seven volts. Thestorage battery 170 is a six volt storage battery. Therefore, the dioderectifier 158 is back biased, thereby preventing current ow therethroughfrom storage battery 170. Thus, the B- terminal 161 delivers minus sevenvolts D.C. poten# tial to the line 163 which is connected to the B-supply line 31. Accordingly, the B+ terminal 171 delivers plus 7 voltsD.C. to the line 173 which is connected to the B| supply line 41. 1twill be noted that the storage battery 170 is not connected to thedevice of the present invention so long as the 110 volt, A.C. powersupply is inductively coupled to the secondary 162 of power transformerT-1. However, should there be a disruption in the 110 volt, A.C. voltagesupply, the voltage at terminal 161 will fall to below minus 7 voltsD.C. thereby rendering diode rectiiier 153 forward biased and connectingthe storage battery 170 to the device of the present invention.

Accordingly, the operation of the device of the present invention doesnot rely upon the existence of conventional 110 volt, 60 cycle A.C.supply since upon the loss of the 110 volt, A.C. supply the storagebattery 170 will be connected to the device of the present invention andprovide the operating potentials needed thereby. It is to be thereforeunderstood that the device of the present invention not only -operateswhen the conventional ll() volt, 60 cycle, A.C. supply is unavailable,but also permits removal of the device from the 110 volt, A.C. socketcommonly found in the home or other sites and may be used as a portableself-contained warning device which can be carried by the ownerthereof'during an alert or dis aster. That is to say, notwithstandingthe existence of 110 volts A.C. supply, the device of the presentinvention provides an audible alarm of the existence of an impendingdisaster or national emergency, and in the case of enemy bomber ormissile attack, the owner of the device may remove it from the wallsocket of the home and carry it with him to the shelter area, therebypermitting continuous and uninterrupted reception of information andinstructions during the alert or emergency.

The decoder portion of the present invention is shown in the middlesection of FIGURE 2 and it utilizes only that portion of the conelradcode which consists of live second intervals of presence and absence ofstandard broadcast station carrier waves. That is to say, the decoder isresponsive to the conelrad code which comprises a rst carrier OFF periodof five seconds, followed by a first carrier ON period of five seconds,and followed by a second carrier OFF period of tive seconds. The decoderportion of the present invention is clearly not responsive to the nextfifteen second period of the conelrad code, to wit, when the carrierwave is modulated with a 1000 cycle signal. Thus, the audio output ofthe device of the present invention will be muted, that is to say,nothing will emit from the speaker 80 until the de- 6 coding portiondetects the tive second intervals of presence and 'absence of standardbroadcast carrier waves. Then, and only then, will the device connectthe speaker to the output of transistor TR-3 so as to give an audiblealarm to alert the owner of the device of the impending disaster ornational emergency.

The signal used to activate the decoder portion of the device is theA.V.C. voltage commonly developed and available in superheterodyne radioreceivers. The A.V.C. voltage is fed to the base 82 of transistor TR1and will render transistor TR-l conductive when the conelrad code signalis received by the radio receiver. The emitter 86 of transistor TR-l isconnected to B terminal 161 via line 163 and the collector 84 oftransistor rI`R-1 is connected to the upper end of coil S8 of relay K-1.The lower end of coil 88 of relay K-1 is connected to the B+ terminal171 via line 173. The relay K-l comprises upper and lower contacts 92and 94, respectively, and a swinger adapted to engage contacts 92 orl94. The swinger 90 is connected to the B- terminal 161 via line 163.

The decoder portion of the device of the present invention comprises amotor 150 which is connected to a disc 101. The disc 101 has two slots147 and 149 cut therein. The slot 147 is ten degrees in arcuate lengthand slot 149 is thirty degrees in arcuate length. Physically locatedabout the periphery of disc 101 are switches SVV-1, SW-2, SVV-3, SW-4and SW-S. The thirty degree slot 149 is positioned radially from thecenter of disc 161 so as to move the swingers 116, 110, and 100 ofswitches SW-1, SW-Z, and SW3, respectively, from the position shown inthe drawing to the position shown by the dotted lines when the swingersare within the slot 149. The ten degree slot 147 causes swingers 120 and130 of switch SW-4 and SW-S, respectively, to move from the positionshown in the drawing to the position shown by the dotted lines when theswingers thereof are within the slot 147. The switches SW-l, SW-Z andSW-3 are not affected by slot 147 and switches SW-4 and SW-S are notatected by slot 149. The motor 150 has two terminals 152 and 154.Terminal 152 is connected to swinger 130 of switch SW-5 and terminal 154is connected to the B-iterminal 171 via lead 153.

Referring now to the circuit connections of switches SW-1 to SW-S, theswinger 116 of switch SW-1 is connected to one end of resistor 104, andthe other end of resistor 104 is connected to contact 94 0f Vrelay K-land Contact 12S of switch SVV-5. The swinger 119 of switch SW-2 isconnected to resistor 102 and the other end of resistor 102 is connectedto contact 92 of relay K-l and contact 124 of switch SVV-4. The swinger100 of switch SVV-3 is connected to Contact 94 of relay K-l. The swingerof switch SW-4 is connected to contact 126 of switch SW-S and swinger ofswitch SW-S is connected to terminal 152 of motor 150. ontact 114 ofswitch SVV-1, contact 10S of switch SW-2, and contact 93 of switch SW-3,are each connected to lead 131 which is connected to one end oflresistor 132. The other end of resistor 132 is connected to the base140 of transistor rl`R--2. Contact 112 of switch SW-l, contact 106 ofswitch SVV-2, and contact 96 of switch SVV-3, are not connected to thedevice of the present invention and merely act as means for holding therespective swingers of the switches SVV-1 to SW-3 in the positions shownin FIGURE 2. Contact 118 of switch SW-4 is connected to B terminal 161via lead 121.

Referring now to the middle rightha-nd portion of FIG- URE 2 wherein themeans for connecting the speaker S0 to the output transformer T-2 isshown, the base 140 of transistor "fR-2 is connected to B-lsupply line41 through the capacitor 134 and the emitter of that transistor isdirectly connected to the B+ supply line 41. The collector 136 oftransistor TR-Z is connected through coil 144 yof relay K-Z to the B-supply line 31. The upper end of coil 144 of relay K-Z is connectedthrough resistor 142 to terminal 76 of switch SVV-6. When coil 144 ofrelay K-2 is energized, contacts 147 of that relay will close therebyconnecting speaker 80 across the secondary -62 of transformer T-2.Terminal 146 of relay K-2 vis connected to terminal 63 of speaker 80 andterminal 148 of relay K-Z is connected to terminal 61 of secondary 62 ofoutput transformer T-2.

Referring now to the upper righthand portion of FIG- URE 2, there isshown a double-pole double-throw switch SW-6 which comprises listenterminals 72 and 74 and alarm terminals 76 and 78. When the switchSW-iis in the alarm position the device of FIGURE 2 operatively couplesthe speaker 80 across the transformer T-Z thereby permitting the 1000cycle signal of the standard broadcast station carrier wave to becoupled across and reproduced by the speaker 80 when the conelrad codeis transmitted and relay K-Z subsequently energized.

Further, when the switch SW-6 is in the listen position the speakerSO-isconnected across the transformer T-2 for coupling and reproducinginstructions which may be transmitted over either the standard broadcaststation frequencies or over the conelrad broadcast frequencies, exceptthe regenerative feedback feature (to be discussed in detailhereinbelow) otherwise provided by capacitor 81 is not provided.

Thus, when the switch SW-6 is in the alarm position, an audio outputfrom speaker 8i) is possible only when the conelrad code is beingtransmitted by either a standard broadcast frequency or a conelradbroadcast frequency, but when switch SW- is in the listen position, anyaudio modulated intelligence transmitted over the standard broadcastfrequencies or the conelrad frequencies will be reproduced by speaker80, irrespective of the conelrad code.

Referring now to the circuit connections of switch SVV-6, the terminal7S thereof is connected to the base 32 of transistor TR-4 via the seriescircuit including capacitor 81, resistor 22, pointer 26 of resistor 22,andV capacitor 24. Thus, when the switch SW-6 is in the alarm positionthe amplified signal coupled across transformer T-Z for reproduction bythe speaker 80 is fed back to the base TR-4 via the above mentionedseries circuit. This feedback feature provides a regenerative featurewhereby the amplitude of the signal being reproduced by speaker 80 isincreased thereby enhancing the possibility that the owner of the devicewill hear the audible alarm developed thereby. The terminal 61 ofsecondary 62 of transformer T-2 is connected to terminal 74 of switchSW-6 and the terminal 63 of speaker 80 is connected to terminal 73 ofswitch SW-6, thereby effectively connecting speaker 80 across secondary62 of transformer T-2 when switch SW-6 is in the listen position.Terminal 75 of switch SW-6 is connected to B-lsupply line 41 therebyAproviding the biasing potential for the collector 136 of transistorTR-Z when switch SW- is in the alarm position through the series circuitincluding resistoi 142.

Accordingly when switch SW-6 is moved to the listen position resistor142 is disconnected from the B+ line 41 de-energizing coil 144 of relayK-2 and openingtcontacts 147 of that relay.

Referring to the upper middle portion of FIGURE 2, there is shown thestandard-conelrad selector switch SW-7, which is connected tothesuperheterodyne transistorized radio receiver 20. When the switch SW-7is in the standard position the radio receiver 20 is rendered capable ofreceiving transmitted carrier waves within the conventional AM or FMband as well as the conelradV frequencies, and when in the conelradposition, the radio receiver is rendered capable of receiving theconelrad frequencies only, to wit, 640 kc. or 1240 kc.

Cycle of operation that a conelrad code is not being transmitted, i.e.,the standard broadcasting stations carrier waves are being transmittedin a conventional and normal manner, the automatic volume controlvoltage developed by the radio receiver 20 is insufficient to rendertransistor TYR-1 conductive. Accordingly, since the speaker is connectedacross the secondary 62 of Vtransformer T-2 through contacts 147 ofrelay K-Z, any audio signal developed across primary 60 of transformerT-2 will not be reproduced by speaker .80.

Assuming now that the conelrad code is being ltransmitted, to wit, alltransmission of standard broadcast station carrier waves will bediscontinued (OFF) for a live second period, then transmitted (ON) for ative sec-Y ond period, then discontinued (OFF) for a live second period,then transmitted (ON) for a fifteen second period with a 1000 cyclesignal applied there-to, then transmitted (ON) for an indefinite periodwith audio instructions and information applied thereto. When thestandard broadcast station carrier is discontinued (OFF) during thefirst live second interval of the conelrad code, the automatic volumecontrol (AVC) voltage of the radio receiver 20 is no longer present orat a voltage level sufficient to render transistor T R-1 non-conductive.That is to say, when a carrier Wave is received by the radio receiver 20there is sutiicientnegative voltage developed by the automatic volumecontrol circuit of the receiver 20 to render the transistor TR-lnon-conductive. Thus, when the standard broadcast station carrier waveis OFF during the first five second period of the conelrad code,transistor TR-l is rendered conductive, thereby energizing coil 88 ofrelay K-l, which is turn causes swinger 90 of that relay to engagecontact 94.

Referring for a moment to the disc 101, it will be recalled that theposition of slots 147 and 149 as shown in FIGURE 2 is the normalposition thereof when the decoder portion of the present invention is inreadiness for a cycle of operation. Therefore, swinger 130 is-in theposition shown by the dotted lines since the swinger 130 is in the l0degree slot 147 of the disc 101.

Referring again to relay K-1, when that relay is energized, motor 150 isalso energized since voltage is applied thereto through the circuitincluding B- terminal 161, lead 163, swinger 90, contact 94, lead 127,contact 128, swinger 130, lead 151, terminal 152, terminal 154, lead153, and B-lterminal 171. Thus, the motorwill commence to rotate thedisc 101 clockwise and cause the swinger 130 lto subsequently move toits normally closed. position, i.e., in engagement with contact 126 ofthat switch, since the slot 147 will move away from the swinger 130 as.the disc 101 rotates. To insure that the motor will continue to runafter the swinger 130 moves out ofthe slot 147 of disc 101, contact 126is connected viarlead to swinger 120` of switch SW-4. Thus, energizingpotential for motor 150 is not disconnected when swinger moves to itsnormal position, but is provided through the circuit including B-terminal 161, lead 121, contact 118, swinger 120, lead 125, contact 126,swinger 130, lead 151, terminal 152, terminal 154, lead 153, and B+terminal 171. Thus, the motor Y will continue to run until switch SW-4is caused to open, i.e., to move to the position shown by the dottedlines.

Referring now to slot 149 of disc 101, the swinger 116 of switch SW-lwill be in the slot 149 during the first five second period of theconelrad code and therefore swinger 116 will be in engagement withcontact 114 of that switch. The angular speed of disc 101 and the thirtydegree arcuate distance of slot 149 are so related that the swinger 116will be caused to be in engagement with contact 114 for a tive secondperiod which corresponds to the first five secondv period of theconelrad code.

During the live second period that swinger 116 is in engagement withcontact114, the lcondenser 134 con- 9 nested to the base 140 oftransistor TR-2 is caused to be charged to a predetermined voltage levelthrough the charging path including B supply line 31, swinger 90,contact 94, lead 127, resistor 104, swinger 116, contact 114, lead 131,resistor 132, capacitor 134, and B+ supply line 41.

During the second five second period of the conel-rad code, relay K4 isde-ene'rgized and swinger 90 returns to its normal position, i.e., inengagement with contact 92 of that relay. During this second period ofthe conelrad code, swinger 110 of switch SW-Z is positioned within slot149 and caused to engage contact 108 of that switch. When swinger 110 islin engagement with contact 108,- the capacitor 134 is again charged toa second predetermined voltage level through the charging path includingB- supply line 31, swinger 90, contact 92, resistor 102, swinger 110,Contact 108, lead 131, resistor 132, capacitor 134, and B+ supply line41.

During the third five second period of the conelrad code relay K-l Iisagain energized and swinger 90 caused tov again engage contact 94 ofthat relay. During this five second period of the conelrad code, swinger100 of switch SW-3 is positioned within slot 149 and caused to engagecontact 98 of that switch. When swinger 100 is in engagement withcontact 98, the capacitor 134 is `again charged to a third predeterminedlevel through .the charging path including B- supply line 31, swinger90, contact 94, swinger 100, contact 98, lead 131, resistor 132,capacitor 134, and B+ supply line 41.

Thus, it will be noticed that (l) the switching time ofswitch SW1corresponds to the first five second carrier OFF period of the conelradcode, (2) the switching time of switch SW-Z corresponds to the firstfive second carrier ON period of the conelrad code, and (3) theswitching time of switch SW-3 corresponds to the second carrier OFFperiod of the conelrad code.

It is to be also noted that the series combination of resistor 104,resistor 132 and capacitor 134 during the .rst tivesecond carrier OFFperiod of the conelrad code and resistor 102, resistor 132, andcapacitor 134 during the first ON period of the conelrad code, eachconstitute an integrating circuit. Thus, the amount of voltage that willbe developed across capacitor 134 will be proportionalto the voltageapplied, the resistance of resistor 132 plus either the resistance of102 or 104, and the amount of time that the voltage is applied tocapacitor 134. `Clearly, the higher the resistance of theintegrating'circuit, the less charge the capacitor 134 will take andtherefore the smaller the voltage will be which isv developed across thecapacitor 134 during the five second intervals of the conelrad code. Theresistance of resistors 102, 104 and 132 are so related that the amountof voltage developed across capacitor 134 will be equal during each ofthe switching periods of switches SW-1 to SW-3. Accordingly, during eachfive second interval of the conelrad code, the capacitor 134 will becharged to a predetermined level in increments of three equal voltagevalues. v

- ;At the completion of the three consecutive five second chargingperiods of capacitor 134, the voltage across 134 will be sufficient torender transistor 'FR-2 conductive, thereby energizing coil 144 of relayK-2 and causing contacts 147 of that relay to close. When contacts 147of relay K-Z are closed, terminal 61 of secondary 62 of transformer T-Zand terminal 63 of speaker 80 are connected together, therebyA placingspeaker 80 across secondary 62. Accordingly, .the 1000 cycle signaldevelvoped across primary 60 of output transformer T-2 will be coupledto secondary 62 and reproduced by speaker 80.

Recalling for a moment that switch SW-6 has two positions, i.e., analarm and listen position, when this switch isin the alarm position,resistor 142 is connected through contacts 75 and 76 of switch Svi/'+6to the B+ supply line -41, thereby completing a current path throughcoil 144 of relay K-Z. The amount of current through the lastmentionedcurrent path, though insuficient to close contacts 147 of that relay, issufcient to hold the contacts closed after transistor TR-2 has providedsufiicientcurrent ow through coil 144 (energized the coil) to close thecontacts. Therefore, the subsequent return of transistor 'TR-2 to itsnormally non-conductive state after the capacitor 134 has dischargedtherethrough will not result in the opening of contacts 147 of relayK-2.

Further, when switch SW-6 is in the alarm position, contacts 73 and '78of that switch also provide a regenerative feedback path from secondary62 of output transformed T-Z to the input portion of amplifyingtransistor TR-4 through condenser 81. Thus, an enhancement in the volumeof the 1000 cycle signal being reproduced by speaker is provided so thatthe possibility of not hearing the warning signal is considerablyreduced, or conversely the audio range of the device is considerablyincreased.

Referring back to disc 101, after slot 149 has cleared swinger 100, thefourth period of the conelrad code commences, that is, the broadcaststation carrier frequency (or conelrad frequencies) is modulated with a1000 cycle signal and transmitted for fifteen seconds. During thisperiod of the conelrad code, the relay K-l will be de-energized andswinger will be in engagement with contact 92 of that relay. Whenswinger 120 engages slot 147 during this fifteen second period of theconelrad code, the swinger moves to the position as shown by the dottedlines and motor 150 will remain energized through the current pathincluding B'- terminal 161, lead 163, swinger 90, contacts 92, lead 123,contact 124, swinger 120, contact 126, swinger 130, terminal 152,terminal 154, lead 153, and B+ terminal 171.

When the swinger thereafter engages the slot 147 the motor will stopsince energizing voltage is no longer applied thereto through relay K-lwhich is now deenergized. That is to say, when swinger 130 engagescontacts 123 the motor energizing path is broken since contact 128 isconnected to `contact 94 of relay K-l and relay K-l is de-energized withswinger 90 engaging contact 92, as shown.

Thus, the decoder portion of the device of the present invention is nowin readiness for a subsequent conelrad warning signal code.

Referring back to switch SW-6, after the regenerated 1000 cycle warningsignal has been reproduced 'by speaker 80, the user of the device of thepresent invention may switch from the alarm to the listen position. Whenin the listen position, the reproduction of signals coupled to secondary62 yfrom primary 6i) of a transformer T-2 is not dependent upon theclosure of contacts 147 of relay K-Z. This is so because terminals 73and 74 of switch SW- connect terminals 61 and 63 of secondary 62 andspeaker S0, respectively, thereby shorting out the contacts 147. Also,when in the listen position, the regeneration of the audio output viacapacitor 81 is disconnected, as in the application of negative p0-tential to coil 144 of relay K-Z through resistor 142. Thus, coil 144 isde-energized and contacts 147 open and any subsequent moving of switchSW-6 to the alarm position will not result in contacts 147 closingsince, as above mentioned, the current flow therethrough as a result ofthe current path including resistor 142, is insuflicient to close thecontacts 147. Accordingly, when switch SW-6 is in the listen position,the device of the present invention operates as a conventional radioreceiver.

Referring to the middle upper portion of FIGURE 2, there is shown aswitch SW-7 which is a standard broadcast frequency or conelradfrequency selector switch. That is to say, when switch SW-7 i-s in theposition as shown, the device of FIGURE 2 operates to decode theconelrad signal code which is applied to the standard broadcast stationfrequency (and conelrad frequencies) and to give a warning of animpending and imminent i l.' national' emergency. Whereas, when switchSW-7 is putin the conelrad position, the radio receiver 20- isautomatically tuned to the conelrad frequency, to wit, 640 kc. or 1240kc., and decodes only when the conelrad warning signal code istransmitted over conelrad frequencies.

It is to be understood that although the disc 101 is shown and describedin detail as having slot members 147 and 149 formed therein, any otherwell known rotatable switch actuating member may be used to open andclose switches SW-1 to SW-S in the above mentioned predetermined order.By way of example, slots 147 and 149 could be detents or cammingsurfaces and the swinger-s of switches SW-I to SW5 may be cam followerswhich vvould move from the positions shown by the heavy lines to thepositions shown by the dotted lines when the detents or camming surfacesengage the respective swingers.

Still further, it is to be understood that although the device of thepresent invention has been described in detail with reference to thepresent conelrad code, to wit, carrier OFF five seconds, carried ON fiveseconds, carrier OFF tive seconds, 1000 cycle modulated carrier ON fteenseconds, and followed by an audio modulated instruction and informationperiod with the carrier ON, any change of the specificy periods or codeof the conelrad radio warning system may be accounted for in the deviceof the present invention by varying or changing the relationship of thedisc 101 and the switches cooperating therewith in a manner that isobviousvto those skilled in the prior art.

And yet still further, it is to be understood that the device of thepresent invention though described in detail with reference to receptionof the conelrad warning Signal code when transmitted via radiant energy,is equally adaptable to reception of' any national warning system whichmay utilize such signal link means as telephone lines, powertransmission lines, etc., without departing from the scope of thepresent invention.

It is apparent from the above that the present invention provides anovel radio receiver alarm device of relatively simple construction andof a size comparable with portable transistorized radia receivers. Thealarm system of the present invention is operative both day and night,and can be preset or variably tuned to a local or conelrad frequency soat any time that the conelrad alert is transmitted the receiver isautomatically energized and caused to reproduce the 1000 cycle conelradsignal as an audible ysound to warn the owner of the device of the factthat an alert is being given.

Further, the manu-al switch SW-6 provides a feature whereby the `deviceof the present invention may be switched to a listen position withoutproviding the unique regeneration feature, and thereby permitting thedevice to be used as a conventional. radio receiver which is tunable toany station in the broadcast band and wherein the speaker 80 is causedto reproduce the intelligence transmitted by the broadcast stat-ionWithout regeneration. Thus, with the switch SW-6 in the listen position,the device may be removed from the Wall socket fwhich provides the 110,60 cycle, A C. supply of voltage, and carried around by the ownerthereof and used as a portable transistor radio capable of automaticallyWarning the user of an impending or imminent danger being transmitted bythe conelrad radio warning system.

Still further, when the device isV removed from the wall outlet thestorage battery 170 immediately provides the voltages necessary tooperate the device for reception of transmitted radio signals.

And yet, still further, there is provided aV second manual switch SW-7which permits the automatic tuning of the radio receiver to the conelradfrequencies so that the device of the present invention constitutes aportable transistor radio preset to the conelrad frequencies forreceiving conelrad radi@ Wmlng Signals.

Vuntil the switch 44 is moved to the listen position.

It will be apparent from ythe foregoing'that the device of the presentinvention is low in cost, rugged in construction and requires verylittle maintenance. The use of a standby storage supply provides economyin'that the life of the battery in conjunction with lthe presentinvention is near the shelf life thereof. f

Further, it will be apparent from the foregoing that the use of thenovel rotating switch actuating disc 101 provides a unique method ofpreventing actuation of the speaker upon the absence of carrier Wavefrequency as a result of standard broad-cast station breakdown or thelike.

Still further, it willv be apparent from the foregoing that the presentinvention is uniquely adapted to obtain all of the ends and objectshereinbefore set forth, together with other advantages which are obviousand inherentin the device.

It will be understood, therefore, that certain features andsubcombinations of utility may be employed without reference to otherfeatures and subcombinations. This is contemplated by and is within thescope of the appended claims.

It is to be understood that the device of the present invention may bereadily vmodified so as `to be responsive to any code signal which maybe adopt-ed by governmental authorities for the purpose of notifying thepopulace of an imminent and -impending emergency without VVdepartingfrom the scope of the invention. Accordingly,

the hereinabove described conelrad signal code system is merelyexemplary of one of the presently adopted civil defense systems to whichthe advice of the present invention is responsive and should not beconstrued as restricting or limiting. By way of example, the device ofthe present invention may be 'modified to be responsive to a signal codesystem which utilizes power transmission lines or telephone lines as themeans for linking the signal between the transmitter and the receiver. Asystem of the latter type has been adopted by civil defense authoritiesand is commonly referred to as the NEAR warning system. Thus, amodification of the device of the present invention so as to beresponsive to the NEAR signal code is clearly contemplated and requiresonly minor circuit changes.

It is to be understood further that the parameters of the regenerativefeedback circuit (S6-58) are preferably designed so as to drive therear-end of the transistor radio (1S-20) into oscillation so that theaudio tone (1000 cps.) reproduced by the speaker 42 will continue Ofcourse, it is not necessary that the rear-end of the radio be ldriveninto oscillation since the 1000 c.p.s. signal transmitted during thefourth interval of the conelrad Asignal code will be heard forapproximately fifteen seconds.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand notrestrictive, the scope of the invention being indicated by theappended claims rather than by thev foregoing description, and allchanges which come Within the meaning and range of equivalencybf theclaims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatents is:

1. A Warning device responsive to a transmitted signal code comprising:a radio receiver having an audio amplilier and an automatic volumecontrol circuit; a speaker; a switch for connecting said speakerto saidaudio amplier; a decoder coupled to said automatic volume controlcircuit and operative 'in response thereto to cause said switch toconnect said speaker to said audio amplifier; said switch including arelay having a coil and normally open contacts; said coi-l'beingenergized by saidA decoder thereby closing said contacts and connectingsaid speaker to said 4audio amplifier; said speaker being operative toreproduce the audio output of said audio amplifier; said automaticvolume control circuit being responsive to said signal code and adaptedto actuate said decoder whereby said lspeaker is caused to reproducesaid audio output of said audio receiver; said decoder including amot-or driven switch actuating means; a plurality of charging switches;storage means; said switch actuating means being responsive to saidautomatic volume control circuit and causing said charging switches tobe sequentially actuated; each of said charging switches being adaptedto charge said storage means to a predetermined voltage level whenactuated by said switch actuating means; said storage means beingadapted to energize said coil of said relay thereby causing saidcontacts of said relay to close.

2. A warning device in accordance with claim 1 wherein said decoderfurther includes: a charging relay responsive to said automatic volumecontrol circuit; a source of potential; said charging relay adapted toconnect said source of potential -to said charging switches whenenergized by said automatic volume control circuit whereby said chargingswitches cause said storage means to charge to a predetermined levelwhen actuated.

3. A warning device responsive -to a transmitted signal code comprising:signal reproducing means, audio amplifying means and automatic volumecontrol means; switch means for connecting said signal reproducing meansto said audio amplifying means; decoding means coupled to said automaticvolume control means and operative in response thereto; said automat-icvolume control means being responsive to said signal code and adapted toactuate said decoding means; storage means for controlling the operationof said switch means; said storage means 'being normally discharged;said switch means being normally in a irst position with said signalreproducing means disconnected `from said audio amplifying means; saiddecoding means adapted to step charge said storage means und-er thecontrol of said automatic volume control means; means for dischargingsaid storage means after said storage means is charged to apredetermined voltage level thereby causing said switch means to move toa second position and connect said signal reproducing means to saidaudio amplifying means.

4. A warning device in accordance with claim 3 wherein: said signalreproducing means being a speaker; said storage means being a capacitor;said switch means including a relay coil for connecting said speaker tosaid audio amplifying means; and said means for discharging said storagemeans being a transistor.

5. A warning device in accordance with claim 4 wherein: said decodingmeans comprises: a motor driven rotary switch actuating means; aplurality of charging Cir switches; -said switch actuating means beingresponsive to said automatic volume control circuit and causing saidcharging switches to be sequentially actuated; said automatic volumecontrol circuit being openative to actuate said decoding means under theinfluence yof said signal code; each of said charging switches being ina normally rst position with said capacitor discharged; a source ofdirect current potential; said switch actuating means being adapted tosequentially move each of said charging switches to a second position;each of said charging switches Iwhen in said second position connectsaid direct current potential to said capacitor thereby causing saidcapacitor to step-charge to a predetermined level.

6. A warning device responsive to a transmitted signal code comprising:a radio receiver having an audio ampliier and an automatic volumecontrol circuit; a speaker; a relay switch including a relay coil forconnecting said speaker to said audio amplifier; a transistor forcontrolling the current flow through said relay coil; a capacitorconnected to the control element of said tnansistor; a decoder coupledto said automatic volume control circuit and operative in responsethereto Aand including a motor driven switch for controlling thepotential across said capacitor; said motor driven -switch including apluraility of contacts for sequentially step-charging said capacitor; aregenerative feedback circuit connected ibettween the input and outputof said audio amplier; said relay switch upon actuation rendering saidfeedback circuit operative; said capacitor upon reaching a predeterminedvoltage level being discharged through said relay coil for actuatingsaid relay switch and connecting said speaker to said audio amplifierwhereby the audio output of said radio receiver is reproduced by saidspeaker.

7. A warning device in accordance with claim 6 wherein: said transmittedsignal code comprises sequential intenvals of code; said motor drivenswitch causes said capacitor to step-charge during each of saidintervals through one only of said plurality of contacts.

References Cited by the Examiner UNITED STATES PATENTS 2,882,390 4/1959Kuhl et al. S25-364 2,958,770 11/1960 Davidson et al 325-392 3,009,05911/ 1961 Stratton et al 325-364 3,010,098 11/1961 Pomeroy 325-3643,056,086 9/ 1962 Brauner S25- 403 OTHER REFERENCES Oliphant, L. D.: AConelrad Monitor, Radio & Television News, January 1955, pages 99-100relied on.

DAVID G. REDINBAUGH, Primary Examiner.

1. A WARNING DEVICE RESPONSIVE TO A TRANSMITTED SIGNAL CODE COMPRISING:A RADIO RECEIVER HAVING AN AUDIO AMPLIFIER AND AN AUTOMATIC VOLUMECONTROL CIRCUIT: A SPEAKER; A SWITCH FOR CONNECTING SAID SPEAKER TO SAIDAUDIO AMPLIFIER; A DECODER COUPLED TO SAID AUTOMATIC VOLUME CONTROLCIRCUIT AND OPERATIVE IN RESPONSE THERETO TO CAUSE SAID SWITCH TOCONNECT SAID SPEAKER TO SAID AUDIO AMPLIFIER; SAID SWITCH INCLUDING ARELAY HAVING A COIL AND NORMALLY OPEN CONTACTS; SAID COIL BEINGENERGIZED BY SAID DECODER THEREBY CLOSING SAID CONTACTS AND CONNECTINGSAID SPEAKER TO SAID AUDIO AMPLIFIER; SAID SPEAKER BEING OPERATIVE TOREPRODUCE THE AUDIO OUTPUT OF SAID AUDIO AMPLIFIER; SAID AUTOMATICVOLUME CONTROL CIRCUIT BEING RESPONSIVE TO SAID SIGNAL CODE AND ADAPTEDTO ACTUATE SAID DECODER WHEREBY SAID SPEAKER IS CAUSED TO REPRODUCE SAIDAUDIO OUTPUT OF SAID AUDIO RECEIVER; SAID DECODER INCLUDING A MOTORDRIVEN SWITCH ACTUATING MEANS; A PLURALITY OF CHARGING SWITCHES; STORAGEMEANS; SAID SWITCH ACTUATING MEANS BEING RESPONSIVE TO SAID AUTOMATICVOLUME CONTROL CIRCUIT AND CAUSING SAID CHARGING SWITCHES TO BESEQUENTIALLY ACTUATED; EACH OF SAID CHARGING SWITCHES BEING ADAPTED TOCHARGE SAID STORAGE MEANS TO PREDETERMINED VOLTAGE LEVEL WHEN ACTUATEDBY SAID SWITCH ACTUATING MEANS; SAID STORAGE MEANS BEING ADAPTED TOENERGIZE SAID COIL OF SAID RELAY THEREBY CAUSING SAID CONTACTS OF SAIDRELAY TO CLOSE.